The present invention relates to (1) a composition contained in a releasing container such as an aerosol container or pump type releasing container, and used as being released from such releasing container, and (2) a releasing container product containing such composition.
As general forms of use of water-soluble or water-insoluble chemicals (for instance, perfume or insect repellent composition for humans or animals), they are widely sold as aerosol products or pump type releasing container products. In the form of an aerosol product, a container having an injection valve is packed with a releasing composition such as a chemical, and a high pressure propellant, and by opening the injection valve, the chemical is injected out of the container together with the high pressure propellant. In the form of a pump type a releasing container product, a container having a releasing pump is packed with a releasing composition such as a chemical, and the chemical is injected out of the container by manually manipulating the releasing pump.
In blending of the content of the aerosol product, for example, an aerosol can of 90 to 160 ml in capacity is filled with 2 to 15 wt. % of chemical such as perfume or repellent, 25 to 35 wt. % of isopropyl alcohol, and 60 wt. % of chlorofluorocarbon, and in its method of use, by pressing a button, the injection valve is opened, and it is sprayed and used in proper positions by the pressure of chlorofluorocarbon.
However, when sprayed or applied in the human living space by using the spray of such conventional blending, in the environments of high temperature in summer, for example, the chemical is evaporated soon, and its effect does not last longer than several hours. If prepared in an emulsion form, it is evaporated soon, too.
Such problems can be solved by carrying the chemical on inorganic porous fine particles, sealing in the container together with other liquid, and releasing. The chemical held in the pores of the inorganic porous fine particles is gradually evaporated after being sprayed, and the chemical effect lasts for a relatively long time.
The inorganic porous fine particles are solid, and form a powder phase when gathered together, and therefore it is necessary to disperse them uniformly in the container. However, when inorganic porous fine particles are dispersed in the conventional liquid, although they are dispersed right after stirring, they sediment as the time passes, and are separate from the liquid if transferred by the pressure of propellant or pump, and the dispersion is not uniform.
On the other hand, Japanese Patent Application laid open No. 7-126104 discloses, as an insect repellent composition for humans, use of silicic anhydride with a specific surface area of 500 m.sup.2 /g or more, as the composition not whitened, long in repellent efficacy, and excellent in feel of use. Japanese Patent Application laid open No. 9-208406 discloses the art of defining the pore volume at 1 ml/g or less, mean pore size at 100 angstroms or less, and specific surface area at less than 500 m.sup.2 /g, as the condition of silicic anhydride fine particles to be used for achieving the same purpose as the insect repellent composition. Moreover, Japanese Patent Application laid open No. 9-157107 discloses, as aerosol for insect repellent, use of a composition containing hydrocarbon of low boiling point, with an injection amount per 3 seconds of 2.0 to 5 ml, and oil absorption amount of powder of 250 ml/100 g or less. Incidentally, UK Patent Specification No. 987,301 "Aerosol Compositions" discloses an art for obtaining an aerosol product by filling a pressure-proof can with powder having drug effects such as an antiperspirant and deodorant, together with alcohol, dispersant, and silicic anhydride fine particles as crude solution, and further adding propellants such as chlorofluorocarbon or LPG.
It is hence a first object of the invention to carry a chemical on inorganic porous fine particles, enhance the sustained-release effect of the chemical, and disperse the inorganic porous fine particles as the powder phase (solid phase) more uniformly in a disperse solution. That is, it is intended to enhance the dispersion performance of the inorganic porous fine particles.
It is another object of the invention to make it easy to maintain the disperse state of the inorganic porous fine particles in the disperse solution as powder phase (solid phase) when sealed into the aerosol container together with the propellant. More specifically, a stock solution completed as liquid of favorable dispersion is contained in an aerosol can (container), and a valve is attached, and when filled with a propellant, the dispersion in the aerosol composition may be impaired due to the characteristic of the propellant. For example, it is often a problem of pH in the case of carbon dioxide, or it is a problem due to compatibility of stock solution and propellant in the case of liquefied gas. Therefore, desired active ingredients may not be used and, it is hard to find substitutes, or it takes a tremendous time to search the disperse solution, active agent or solvent. It is hence a second object of the invention to suppress lowering of dispersion performance in the container as far as possible, by minimizing the effects from propellant or other contents, regarding the dispersion performance of inorganic porous fine particles. That is, it is intended to prevent lowering of the dispersion performance of inorganic porous fine particles due to propellant.
Other problems include a problem of re-dispersion of the powder phase. However the dispersion performance may be improved by achieving the first and second objects of the invention, the true specific gravity of the powder phase (solid phase) of the disperse phase is, for example, about 2.15, whereas the specific gravity of the disperse solution to be used is, for example, about 0.82. Therefore, when the product is let stand for 10 days, 20 days, or several months, the solid phase settles in the bottom of the liquid. It depends on the art of the engineer how to disperse it again easily, by such simple operation as to hold and shake the container one or two times. That is, it requires various experiments in selection and combination of dispersant, moisturizer and active agent, adjustment of liquid viscosity, powder particle size, bulk specific gravity, surface treatment, and others. It is hence a third object of the invention to re-disperse inorganic porous fine particles smoothly.
Another problem is to emphasize the merits the of powder phase, that is, the silicic anhydride porous fine particles, and to conceal the demerits. Advantages of inorganic porous fine particles are to extend the drug effect by carrying the active ingredients, prolong the retention time of the inorganic porous fine particles by developing on the skin surface, and avoid sticky feel on the skin surface. However, if the inorganic porous fine particles are used excessively, due to stiffness of the inorganic porous fine particles, a stiff feel is expressed, and dry or smooth feel is lost. It is hence a fourth object of the invention to improve the touch on the skin surface if applied on the skin, that is, to give a dry and smooth feel of use.
Moreover, when the inorganic porous fine particles are dried, they appear white, and a strange feel is given visually. It is hence a fifth object of the invention not to give a strange feel visually, that is, not to whiten.